Fine-needle aspiration cytology vs. core biopsy in the diagnosis of breast lesions

Fine-needle aspiration cytology (FNAC) is an established, highly accurate method for diagnosing breast lesions. However, in recent years there has been increased use of core biopsy (CB) in this setting. The aim of this study was to evaluate the accuracy of FNAC and compare the quality assessment parameters of FNAC and CB in palpable and nonpalpable breast lesions. Data regarding FNAC, CB, and excision biopsy (EB) diagnoses were retrieved from the archives of our department. A total of 4,367 FNAC samples from the years 1999-2001 was reviewed. Of these, corresponding histology results were available for 1,275 lesions, of which 1,248 were primary breast epithelial lesions (788 EB, 199 CB, 261 EB+CB). All cases were analyzed for sensitivity and specificity of FNAC. Cases with both FNAC and CB were compared and quality assessment parameters were calculated using the methodology detailed in the National Health Service Breast Screening Program guidelines. High specificity and sensitivity, as calculated for satisfactory specimens, were achieved with the use of both FNAC and CB. False-positive and false-negative diagnoses were seen in 7/404 (1.7%) and 45/635 (7.1%) of biopsy-proven specimens sampled by FNAC. The corresponding values for CB were 0% and 5.7%, respectively. Inadequate sampling (15.1%) with use of FNAC was particularly seen in collagenous lesions and in submitted specimens sampled by physicians lacking experience with the FNAC procedure. FNAC is a valuable method, although moderately less sensitive than CB. CB is the preferred method for preoperative diagnosis when sampling FNAC provides scarce material and suspicion of a fibrotic and collagenous lesion such as lobular carcinoma and radial scar arises. FNAC is most accurate when experienced cytologists are available and when immediate assessment by professionals is performed for evaluation of material adequacy, so that additional aspirations can be done when needed.